Silver halide photographic emulsions containing phenozine-n-oxides desensitizers

ABSTRACT

Photographic silver halide emulsion and photographic elements containing same, said elements containing certain phenazine desensitizing dyes. The dyes of this invention selectively desensitize the silver halide emulsion to visible light, as contrasted with X-rays.

ilited States Patent Shiba et al. 51 Apr. 25, 1972 [541 SILVER HALIDE PHOTOGRAPHIC EMULSIONS CONTAINING References Cited PHENOZINE-N-OXIDES UNITED STATES PATENTS DESENSITIZERS 3,403,025 9/1968 Rees et al. ..96/10l [72] Inventors: Keisuke Shiba; Reiichi Ohi; Masatoshi Su- 3 250 3 5 19 Stewart et l 9 101 X giyama; All! Ohhashi; Momhiko Tsub- 3,340,063 9/1967 Kalenda ....96/10l x of Kanagawa, Japan 3,237,008 2/1966 Dostes et al ..96/10l x [73] Assignee: Fuji Photo Film Co., Ltd., Ashigara- Kamigum, Kanagawa, Japan Primary ExammerNorman G. Torchm Assistant Examiner-Won H. Louie, Jr. [22] Fled: Man 1970 Attorney-Sughrue, Rothwell, Mion, Zinn& Macpeak ["21] Appl. No.: 17,316

[57] ABSTRACT [30] Foreign Application Priority Data Photographic silver halide emulsion and photographic elements containing same, said elements containing certain Mar. 7, Japan henazine desensitizing dyes The dyes of this invention elec. tively desensitize the silver halide emulsion to visible light, as [5 U.S. Cl ..96/10l contrasted i x {51 ..G03c 1/36 [58 Field of Search ..96/ 101 5 Claims, No Drawings SILVER I'IALIDE PHOTOGRAPI'IIC EMULSIONS CONTAINING PI-IENOZINE-N-OXIDES DESENSITIZERS BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silver halide photographic emulsion having selectively reduced sensitivity to visible light and, more particularly, to a silver halide photographic emulsion of which the sensitivity to visible light has been reduced without reducing sensitivity to X-rays.

2. Description of the Prior Art Usually, photographic light-sensitive elements must be developed, after image exposure, in a dark room or under safe light and the development must also be conducted, in general, under controlled conditions of temperature, time, agitation and the like. Thus, as these developing operations must be conducted in a dark room or under safe light, various attempts have been made to allow the conducting of these operations under more convenient conditions.

In ordinary silver halide photographic emulsions, the sensitivity thereof to X-rays is in direct proportion to sensitivity to visible light.

An object of the present invention is to provide a specific silver halide photographic emulsion, the sensitivity of which to visible light has been selectively reduced without reducing the sensitivity thereof to X-rays, whereby it becomes possible to handle the light-sensitive element made from such a light-sensitive photographic emulsion under visible light after the lightsensitive element is exposed to X-rays.

Another object of the present invention is to provide a desensitizing agent capable of reducing selectively the sensitivity of a silver halide photographic emulsion to visible light without reducing the sensitivity thereof to X-rays.

Still another object of the present invention is to provide a silver halide photographic X ray-sensitive element having a silver halide emulsion layer containing the desensitizing dye as mentioned above.

In this respect, by using an ordinary desensitizing dye, such as pinakryptol yellow, phenosafranine, methylene blue and the like, the sensitivity of a silver halide photographic emulsion to X-rays may be reduced considerably, but these materials tend to remain after development as stains.

SUMMARY OF THE INVENTION The inventors have found that the above objects of the present invention can be attained by incorporating into a silver halide photographic emulsion a compound represented by the general formula wherein R R R and R each represents a hydrogen atom, an alkyl group (e.g. lower alkyl), an aryl group (e.g. phenyl), a nitro group, a hydroxyl group, an alkoxy group eg lower alkoxy), a halogen atom, an amino group or a substituted amino group, or said R, and R or said R and R may be condensed with each other to form a benzene ring.

DETAILED DESCRIPTION OF THE INVENTION Examples of alkyl substituting groups of the phenazine oxide derivatives represented by the above mentioned general formula are lower alkyl groups, such as methyl, ethyl, butyl and the like. Examples of halogen atoms are chlorine, bromine and the like and examples of substituted amino groups are lower alkyl-substituted amino groups, such as alkyl amino, dialkyl amino, and acylamido group, and the like.

The use of phenazine derivatives as desensitizing dyes is known but it has never been known that the phenazine oxide derivatives employed in the present invention selectively desensitize a silver halide photographic emulsion to visible light while having much less effect upon the sensitivity of the emulsion to X-rays.

Moreover, the aforesaid compound to be used in the present invention has the advantage that when the compound is incorporated into a silver halide photographic emulsion layer of a photographic light-sensitive element, less stain is left after the light-sensitive element is developed and, further, since the absorption wave length of the compound is in the short wave length region, any stain which may remain after development, is inconspicuous.

The aforesaid phenazine oxide derivative used in the present invention may be incorporated into a silver halide photographic emulsion as a solution in a water-miscible organic solvent such as methanol, ethanol, acetone, pyridine and the like. The amount of the compound to be incorporated in the silver halide photographic emulsion is preferably 1.5 X 10 to l X 10' mole per mole of silver halide in the silver halide emulsion. As the silver halide photographic emulsion, there may be profitably used a silver iodobromide emulsion, a silver bromide emulsion, and a silver chloroiodo-bromide emulsion.

The silver halide photographic emulsion containing the above-mentioned desensitizing dye may be applied to any suitable support, such as a cellulose triacetate film, a polyethylene terephthalate film, a baryta-coated paper, a resin-coated paper or other plastic film.

Typical examples of the aforesaid compounds represented by the above-mentioned general formula are shown below. It should, however, be understood that the invention shall not be limited to only these compounds. The temperatures shown with the compounds are the melting or decomposition points of the corresponding compounds;

Compound Structure C.

I Compound (a) N 222 258 Compound (b) N Com ound (c).. N 154-155 D o 02H;

Compound ((1) N C} 203 Hz 0 O- N Compound (e) C H;

IIIHCOCH;

Compound (1) Compound Compound (k) Compound (1) Com ound m) Compound (n) Compound (p) r 0 Compound (o).. 188490 Compound (q) Nn 161-162 B i N r Compound (1') N m 282 Compound (5) N 01 250 Com ound t N 198 p 0 mow 1;

Br N The aforesaid phenazine oxide derivatives used in the present invention may be prepared by either of the following well known methods:

1. A Wohl-Aue reaction, wherein an aniline or naphthylamine is reacted with a nitrobenzene in a nonpolar solvent, such as benzene or toluene, using potassium hydroxide as the condensing agent.

2. A method wherein a phenazine obtained by the condensation reaction of an o-quinone and and o-phenylenediamine is oxidized using hydrogen peroxide.

The invention will be further illustrated by the following example.

EXAMPLE One kilogram of a gelatino silver iodobromide emulsion (containing 1 mole% iodine) was melted at 40 C. in a beaker.

A desired amount of a methanol solution of the compound of this invention in a desired concentration was added to the system followed by stirring. The resultant silver halide emulsion was applied to a cellulose triacetate film in a thickness of 7.5 microns i 0.5 micron and dried to provide a silver halide photographic light-sensitive film.

The photographic light-sensitive film thus prepared was cut into two portions. One specimen was exposed to X-rays using an X-ray source of 75 k. V. and 6 amp. through an aluminum 3 ,6 5 8 ,5 47 5 6 wedge of a definte thickness. The other specimen was exposed N for 8 minutes to a daylight source through a yellow filter for safe light'(More Light; made by Eastman Kodak Co.) under definite conditions.

The specimen films thus exposed were developed for 4 5 minutes at 20 C. in a developer having the following composition and then fixed Metol 4 g. Anhydrous sodium sulfite 60 g. 10 OH 10 g Hydroquinone \N/ Sodium carbonate mono-hydrate 53 g. 8 Potassium bromide 2.5 g. Water to make 1 liter N 0 0211 The relative sensitivity to X-rays and the density of fog by yellow light of the various specimens were measured, the \N// results of which measurements are shown in the following ta- 1 ble. 0

Amount Relative Fog den- Compound and cone. of the of solution sensitivity sity by yel No. solution of the compound (ml.) to X'-rays low light 1 None 325 3. 2. Compound (:1), 1X10 mo1e.. 20 360 2. 70 40 200 0. 40 80 100 0. 30 20 480 0. 57 40 430 0. 32 80 150 0.20 80 325 0. 200 250 0.20 400 145 0.10 20 360 0. 52 40 350 0. 22 80 200 0.10 80 200 0. 200 200 0.12 400 200 0.10

What is claimed is: C 1. A silver halide photographic emulsion having a reduced sensitivity to visible light and a high sensitivity to x-rays con.-

. moo sisting essentially of a desensitizmg amount of a compound represented by the general formula selected from the group i consisting of CH a N l N R3 11 R4 0 and O T o N I RX Re I CH3 s J1 R4 \N/ wherein R R R and R each is selected from the group consisting of hydrogen, alkyl, aryl, nitro, hydroxyl, alkoxy,

Br halo, amino and substituted amino, and wherein said R and N I R and said R and R together may be condensed with each CH other to form a benzene ring.

2. The silver halide photographic emulsion of claim 1 wherein said compound is incorporated into the silver halide d3 emulsion in an amount offrom 1.5 X 10 to l X 10' mole per mole of silver halide in said emulsion.

3. A silver halide photographic light-sensitive element for NHCOCH3 X-ray photography comprising a support having thereon a layer of silver halide photographic emulsion as set forth in claim 1.

4. The silver halide photographic emulsion of claim 1, wherein said compound is a member selected from the group consisting of \Ny Br and N N Br 5. A silver halide photographic emulsion having a reduced sensitivity to visible light and a high sensitivity to X-rays consisting essentially ofa compound selected from the group con- NHCOCH;

l z v 3) Q U N Br O: n H0 (31 5 and N H 00 N a N Br said compound being incorporated into the silver halide emulsion in an amount of from 1.5 X 10 to l X 10 mol per mol of silver halide in said emulsion. 

2. The silver halide photographic emulsion of claim 1 wherein said compound is incorporated into the silver halide emulsion in an amount of from 1.5 X 10 4 to 1 X 10 2 mole per mole of silver halide in said emulsion.
 3. A silver halide photographic light-sensitive element for X-ray photography comprising a support having thereon a layer of silver halide photographic emulsion as set forth in claim
 1. 4. The silver halide photographic emulsion of claim 1, wherein said compound is a member selected from the group consisting of
 5. A silver halide photographic emulsion having a reduced sensitivity to visible light and a high sensitivity to X-rays consisting essentially of a compound selected from the group consisting of 